Our laboratory is developing several types of oral telemetry which enable direct and continuous measurements of H+ and F- levels following ingestion of various foods and therapeutics. A newly developed wire telemetry device has been developed which allows measurement of five interdental areas simultaneously. This design permits reproducible positioning of the pH sensors when assessing the effects of various foods on the pH levels in dental plaque. The pH responses detected following ingestion of various foods produced pH curves similar to those reported by other investigators. The responses vary within the mouth of a given individual. Data from telemetry coordinated with data from other projects will aid in the evaluation of various food stuffs for their relative cariogenicity.